Merge pull request #9 from kazuminn/add-godocl-link

add godoc link

README.md

diff --git a/README.md b/README.md
index 0ab70d2..c769745 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,6 @@
 # subcommands #
 
+[![GoDoc](https://godoc.org/github.com/google/subcommands?status.svg)](https://godoc.org/github.com/google/subcommands)  
 Subcommands is a Go package that implements a simple way for a single command to
 have many subcommands, each of which takes arguments and so forth.